In a final tribute to the holiday season or just to brighten up the drab winter spirit, try making these wireless LED lights using items you probably have around the house, like pennies and a lemon.
- A lemon
- 3mm LED lights
- 150 grit aluminum oxide sandpiper
- Electrical tape
- Duct tape
- Pennies (at least 10)
- Wrap a piece of duct tape around so that it is sticky on both sides. Press the tape down onto a clear surface.
- Place the penny on the sticky part of the tape facing you. Begin to sand down the surface of the penny until the zinc is exposed. Repeat this process to sand all of the pennies except for one. They should remain copper on the other side.
- Cut the cardboard into at least 9 tiny circular discs that are slightly smaller than the coins. Soak them in freshly squeezed lemon juice.
- Place a sanded penny down on a table with the copper side up.
- Add a damp cardboard disk on top of the penny. Place another penny on top of the cardboard (zinc side down), and then another piece of damp cardboard. Repeat this process for the rest of the pennies and cardboard.
- End the stack with the penny that you did not sand. Then, wrap electrical tape around the cylinder. The tighter, the longer the battery will last.
- Tape the short end of the LED to the intact penny and the long end to the sanded penny. The LED should light up!
- Repeat these steps for the other LED lights.
Pennies are copper on the outside but have a zinc core. When zinc is exposed to acid (like lemon juice), it dissolves and frees electrons, or negatively charged particles. These electrons can be used in a circuit. The battery will continue to run until all of the lemon juice dries up.
Sources: Popular Science